U.S. Investors Find Greener Grass at Home

Plenty of investors, spooked by faltering U.S. growth prospects, have struck out for more exotic locales in hope of snaring juicier returns. They might have been better off sticking closer to home.

The fourth quarter begins Monday with the S&P 500 showing a 14.6% year-to-date gain, thanks in part to advances in the three months just passed. Typically, when U.S. stocks do this well, markets in countries such as China, Russia,...